The present invention relates to a new and distinct cultivar of Barberry plant, botanically known as Berberis thunbergii and hereinafter referred to by the name ‘UCONNBTB048’.
The new Barberry plant is a product of a planned breeding program conducted in Storrs, Conn. The new Barberry plant was developed by exposing pre-germinated seed to the mitotic inhibitor colchicine to create an autotetraploid plant. Specific methods used followed those published in Lehrer, J. M., M. H. Brand, J. D. Lubell, “Induction of tetraploidy in meristematicaly active seeds of Japanese barberry (Berberis thunbergii var. atropurpurea) through exposure to colchicine and oryzalin”, Scientia Horticulturae 119:67-71 (2008). Briefly, seeds were cold stratified for 4-6 weeks and then pre-germinated seeds with 5 -7 mm of radicle emergence were exposed to a 0.1% colchicine solution for 24 hours. The maternal parent plant that provided the seed is Berberis thunbergii ‘Bogozam’ Bonanza Gold. ‘Bogozam’ is a patented variety receiving Plant Pat. No. 8,215 on Apr. 27, 1993. The paternal parent is unknown since the seed used was open pollinated. Treated seeds planted in flats and grown in a greenhouse until they were large enough for ploidy analysis by flow cytometry. Seedlings that were tetraploids were grown on for further evaluation. Tetraploidy was confirmed multiple times by flow cytometry when plants were in containers and the field.
In early 2007, fourteen tetraploid plants were created and grown in a greenhouse and a coldframe for their first growing season. Tetraploid plants were grown outdoors in containers during 2008, 2009 and 2010 and were evaluated for horticultural traits and fruit and seed production. In spring 2011, tetraploid plants were planted in the field for long term evaluation. Diploid Berberis thunbergii ‘Bogozam’ Bonanza Gold plants were grown in the same planting as the tetraploid plants to serve as control plants. During the growing seasons of 2012, 2013, and 2014, tetraploid plants established in the field were evaluated for fruit production, seed production, seed germination and seedling ploidy in comparison to diploid control plants. Berberis thunbergii ‘UCONNBTB048’ was selected from among the 14 tetraploid seedlings based on lack of seed production, compact, dense form, and attractive yellow foliage color.
Asexual reproduction of Berberis thunbergii ‘UCONNBTB048’ by softwood stem cuttings (since 2012) made in late June through early July in a greenhouse or container nursery environment has shown that the unique features of this new barberry plant are stable and reproduced true-to-type in successive generations of asexual reproduction.